Process for decomposition of aluminum nitrate nonahydrate

Claim 1

THE PROCESS FOR DECOMPOSING ALUMINUM NITRATE NONAHYDRATE TO ALUMINA AND NITRIC ACID WHICH COMPRISES: (A) MELTING THE ALUMINUM NITRATE NONAHYDRATE; (B) HEATING SAID MOLTEN ALUMINUM NITRATE NONAHYDRATE TO A TEMPERATURE ABOVE ITS DECOMPOSITION TEMPERATURE BUT NOT ABOVE ABOUT 230*C. UNDER A SUPERATMOSPHERIC PRESSURE OF AT LEAST ABOUT 25 P.S.I.G. AND SUFFICIENT TO MAINTAIN SAID DECOMPOSITION TEMPERATURE, WHILE REMOVING GASEOUS NITRIC ACID DECOMPOSITION PRODUCTS UNTIL BETWEEN ABOUT 45% AND ABOUT 55% OF THE HNO3 OF THE ALUMINUM NITRATE NONAHYDRATE HAS BEEN REMOVED; (C) REDUCING SAID SUPERATMOSPHERIC PRESSURE TO AT LEAST AS LOW AS ATMOSPHERIC PRESSURE WHEREBY ADDITIONAL GASEOUS NITRIC ACID IS RELEASED AND A MOLTEN RESIDUE IS FORMED, WHICH UPON SOLIDIFICATION BECOMES A FRIABLE SOLID; (D) RECOVERING THE SAID NITRIC ACID DECOMPOSITION PRODUCT; (E) COOLING THE RESULTING MOLTEN RESIDUE TO A TEMPERATURE BELOW THE SOFTENING POINT OF THE RESIDUE; (F) MAINTAINING THE RESULTING SOLIDIFIED MELT AT A TEMPERATURE BETWEEN ABOUT 120*C. AND THE SOFTENING TEMPERATURE OF THE SOLIDIFIED MELT FOR A PERIOD OF AT LEAST ABOUT 1/2 HOUR WHEREBY A NON-MELTING, FRIABLE SOLID IS OBTAINED; (G) AND FURTHER HEATING SAID NON-MELTING SOLID AT A TEMPERATURE AT LEAST ABOUT 220C. TO DECOMPOSE SAID NON-MELTING SOLID INTO GASEOUS NITRIC ACID AND SOLID AL2O3.